Citibank’s chief operating officer Douglas Peterson is set to take over at the helm of Standard & Poor’s, as the current president of the latter firm, Deven Sharma, will leave at the end of the year.

Peterson takes over as president on 12 September, and Sharma will spend the rest of his time at S&P working on a special assignment on the firm’s strategic portfolio review. The ratings agency is part of New York-listed The McGraw-Hill Companies.

The change at the top of the firm comes just after it downgraded US sovereign debt from AAA to AA+, to the ire of some wealth managers.

“At best, S&P showed a stunning ignorance and complete disregard for the potential consequences of its actions on a fragile global financial system,” Bill Miller, chief investment officer of Legg Mason Capital Management, said at the time.

But while the firm incurred some criticism over the move, Sharma’s departure is an unrelated matter, the Financial Times reported, citing sources close to the matter.

Peterson was latterly chief operating of Citibank, before which he was chief executive of Citigroup Japan. Before that, from 2001 to 2004, he was the chief auditor of Citigroup.

At present, no further details are known of Sharma’s plans after he leaves the company.